The principal component of most ionizing radiation generators is the ionizing radiation emitter comprising an accelerator of charged particles. The emitter of an X-ray or accelerated electron generator includes an electron accelerator, while that of a neutron generator normally contains an ion accelerator. An ionizing radiation generator may also comprise an emitter power supply and other auxiliary units. The energy ranges covered by the charged particle accelerators forming part of prior art ionizing radiation generators are approximately as follows: 30 to 1,000 keV for X-ray generator, 300 to 1,000-1,500 keV for accelerated electron generators, and 100 to 400 keV for neutron generators involving synthesis of deuterium and tritium nuclei. No particular difficulties arise in designing stationary versions of such accelerators. However, for practical purposes, portable ionizing radiation generators are gaining in importance for they can substantially extend the area of research and other activities necessitating their use, particularly in cases where the object of investigation cannot be delivered to the ionizing radiation generator, e.g. in nondestructive testing of large units or stationary installations, in examining wells, or when such generators are intended for use in mobile laboratories. The application of portable ionizing radiation generators increases the efficiency and productivity, the main advantages being the self-containment and portability of their emitters, which permits, for example, nondestructive testing of a large unit, ensures high mobility, and enables placing them in difficult-to-access spots. The portability of ionizing radiation generator emitters implies, first of all, high values of their specific output parameters, i.e. output parameters relative to the emitter weight or mass, for an emitter featuring higher specific output parameters, such as the mean accelerated electron beam power of a radiation phase, quantum energy of X- or accelerated electron radiation, may replace a more cumbersome emitter with low values of the same parameters. For example, what are considered to be portable emitters of pulsed X-ray apparatus feature low mean accelerated electron beam power of about 2-3 W/kg and low mean X-ray dose at sufficiently high maximum accelerated electron energy of about 20-30 keV/kg (cf. parameters of the IRA-2D apparatus in V. K. Shmelev's "X-Ray Apparatus", "Energiya" Publishers, Moscow, 1973, pp. 408-410 [in Russian]).
In pulsed X-ray emitters it is difficult, in principle, to increase the mean accelerated electron beam power because of the anode design which makes heat removal difficult. Besides, pulsed X-ray emitters are characterized by a short service life, bearing in mind that they have an autoemitting cathode which emits currents of about 10.sup.3 A.
There is known a portable pulsed neutron generator (cf. A. Sh. Allakhverdov et al., "Pulsed Neutron Generator NGI-9 With a Flux of Up To 10.sup.10 n/sec" in "Problems of Nuclear Science and Technology", Radiation Engineering, issue 12, "Atomizdat" Publishers, Moscow, 1975, pp. 182-191 [in Russian]) whose emitter weights about 70 kg and the intensity of the generated neutron flux is 10.sup.10 n/sec. This emitter measuring roughly 300.times.1,000 mm contains a pulsed deuterium ion accelerator (accelerating tube having a source of deuterium ions) and a pulsed high-voltage transformer generating accelerating voltage pulses 150 kV in amplitude and about 1 .mu.sec in duration. The high neutron flux is primarily due to the need to increase the accelerating voltage applied to the accelerating tube up to 300-400 kV. However, the above neutron generator design fails to provide for the same condition at the same size and with the same accelerating tube.
Also known are X-ray apparatus the emitter whereof comprises an accelerating tube and a high voltage source energized from industrial mains (cf. X-ray apparatus "Baltograph 300/3P" manufactured by the Belgian company "Balteau" and described in V. K. Shmelev's book "X-Ray Apparatus", "Energiya" Publishers, Moscow, 1973, pp. 146-147 [in Russian]. The emitter of such apparatus is normally built around a circuit with opposite-phase power supply to the accelerating tube at a total voltage difference of up to 300-400 kV. The specific accelerated electron beam power of such an emitter is about 20 to 30 W/kg, i.e. higher then in pulsed X-ray apparatus. However, the maximum specific accelerated electron energy is only about 5 keV/kg. In addition, attaining, in such a design, an accelerating voltage exceeding 400 kV involves enormous technological difficulties.
There are known X-ray and accelerated electron generators of the "Elita-1" type with an emitter containing an accelerating tube and a high voltage source in the form of a Tesla transformer (cf. Ye. A. Abramyan and S. B. Vasserman, "Heavy Current Pulsed Electron Accelerators". Atomnaya Energiya, vol. 23, issue 1, July 1967 [in Russian]. The specific accelerated electron beam power of such a generator is about 67 W/kg, i.e. the highest of all the generators considered above, and the maximum electron energy is about 8.3 keV/kg (less than in the case of pulsed X-ray apparatus).
Another ionizing radiation generator is known in which the ionizing radiation emitter includes a resonance transformer whose field winding is arranged near the low-voltage end of the step-up winding, electrically associated with the electrically conducting housing of the resonance transformer, and an accelerating tube whose high-voltage electrode is coupled to the high-voltage end of the step-up winding and attached to one end of the tubular insulator of the accelerating tube, the low-voltage electrode is electrically associated with the housing of the resonance transformer, and a charged particle source is provided in the evacuated space of the accelerating tube and electrically associated with one of its electrodes (cf. B. I. Al'bertinsky et al., "Mobile X-Ray Unit Based on Resonance Transformer", Defektoskopiya, No. 5, 1971, pp. 115-119 [in Russian]).
The emitter of this generator is made as an integral unit including an accelerating tube and a resonance transformer and is enclosed in an electrically conducting cylindrical container which is the housing of the resonance transformer, accommodating the accelerating tube arranged coaxially therewith. The casing of the accelerating tube is in the form of a tubular insulator with airtight ends, made up of twelve glass tube sections attached to one another with intermediate metal annular electrodes being sealed therebetween. The tubular insulator terminates, at the end facing the interior of the resonance transformer housing, in the high-voltage electrode of the accelerating tube, secured whereon and coupled whereto is a source of charged particles, or the cathode assembly of the tube. The opposite end of the tubular insulator terminates in the low-voltage electrode which is essentially an external hollow anode associated with the housing of the resonance transformer. The evacuated space of the accelerating tube, wherein the charged particles are accelerated, is confined between the tubular insulator on one side and the external hollow anode on the other.
Arranged above the tubular insulator is the step-up winding of the resonance transformer, whose high-voltage end is connected to the high-voltage electrode of the accelerating tube, and the low-voltage end is electrically associated, via measuring devices, with the housing of the resonance transformer.
The taps of the step-up winding are connected to the intermediate annular electrodes of the tubular insulator of the accelerating tube for a more even distribution of the potentials over its length.
Arranged near the low-voltage end of the step-up winding is the field (primary) winding of the resonance transformer, which is energized from an external power supply whose frequency is adjustable within the range of 430 to 500 Hz for adjusting the operating frequency of the resonance transformer. The space between the tubular insulator and the resonance transformer housing is filled with a gaseous dielectric at a pressure of 10 atm. Electrons are accelerated in the accelerating tube in a direction from the high-voltage electrode to the low-voltge one which is in fact its anode.
The above generator provides for a maximum electron energy of 1,000 keV and a maximum electron beam power of 1,500 W. The X-ray emitter weights 900 kg.
Thus, the maximum specific electron energy of this generator is 1.1 keV/kg and the specific electron beam power is 1.7 W/kg. Such low values of the generator output parameters are due, primarily, to the great thickness of the resonance transformer housing designed for a pressure of 10 atm of the gas filling the space between the housing and the tubular insulator of the accelerating tube, as well as to the large size of the housing, determined by the need to maintain the dielectric strength of the spark gap.